There are a number of known ways to stiffen fabric orthopaedic supports for injured parts of the anatomy. U.S. Pat. No. 4,724,847, for example, discloses an ankle brace that has a plurality of pockets. Rigid stay members are inserted into the pockets to form a rigid structure that surrounds and immobilizes the ankle. U.S. Pat. Nos. 3,298,365, 4,280,488, 4,825,856, and 4,440,158, among others, disclose similar arrangements.
A drawback of these designs is that they require a great deal of labor to construct. Workers must be hired to cut many separate pieces of fabric, sew the supports together, insert the rigid stays and so on. A further drawback is that the stays are typically die-cut from plastic of constant thickness. The shape of the stays is therefore quite limited, and the final support often does not fit the anatomy perfectly.
While stays can be manufactured to have a particular contour, the manufacturing process is not simple and is often fairly expensive. Efforts have been made outside of the orthopaedic support art to create stiffened, custom-shaped objects by injecting hardenable material into a mold in which fabric has been placed. For example, European Patent Application No. 89103277.3, which the EPO published on Feb. 24, 1989 as publication number EP 0 332 899 A2, discloses a diaphragm formed by injection molding plastic onto a piece of fabric. The diaphragm acts as a pressure barrier in an automobile engine. European Patent Application No. 87101406.4, published on Feb. 3, 1987 as publication no. EP 0 234 341 A1, discloses creating fiber reinforced structures for automobiles. Fibrous material is placed into a mold, and then resin is injected into the mold. The resin saturates the fabric and eventually sets, thereby forming a reinforced automobile part. Other examples include U.S. Pat. Nos. 5,093,067 and 5,456,976.
U.S. Pat. No. 5,647,150, which issued Jul. 15, 1997, discloses forming a shoe by stretching a sock about a mold. A thermoplastic film layer is positioned between the mold and the fabric layer. Thermoplastic material is then allowed to flow through the fabric and bond with the thermoplastic film layer, thereby securing the thermoplastic material to the fabric. However, the method requires that the thermoplastic material flow entirely through the fabric in order to bond with a thermoplastic film layer on the opposite side of the fabric.
U.S. Pat. No. 6,024,712, which issued on Feb. 15, 2000 and which is incorporated by reference herein, presents a number of injection-molded orthopaedic supports. The '712 patent introduces the concept of a molded support having a structural member that may optionally be added to the support after the support has already been molded. In particular, FIG. 11 of the '712 patent illustrates an ankle support having an additional frame member that may be optionally secured to the exostructure when further stiffening is required. It is desirable to further extend this concept of easily adapting an already-molded exostructure to the needs of a particular user.